Treatment of microscope specimen slides



United States Patent 9 TREATMENT OF MICROSCOPE SPECIMEN SLIDES Herbert E. Nieburgs, New York, N.Y.

No Drawing. Application June 3, 1957 Serial No. 663,007

8 Claims. (Cl. 167-845) The present invention is directed to the subject of microscopic examination of body cells and more particularly to a method of treating the transparent slides in order to preserve the specimens for such examination.

It has, of course, been common practice to place a smear on a slide and examine it under the microscope. If such smear is allowed to dry in the air, the cells under certain conditions are not suitable for obtaining a clear picture under the microscope. To avoid this the specimen smear is fixed in a mixture of ether and alcohol. However, this is not always done soon enough so that some dehydration takes place. If the slide is to be transferred to the laboratory by mail or other means, the surface of the smear was usually protected by glycerine. However, this could very easily be rubbed off in whole or in part in packing, handling or during shipment and the specimen may thus be damaged. There is also the danger of detachment of cells during the removal of the glycerine in the laboratory.

In order to overcome these deficiencies and disadvantages, it is among the objects of the present invention to provide a method of protecting and fixing the specimen on the slide simultaneously in a single step whereby the slide may be handled without danger of damage to the specimen.

It is also among the objects of the present invention to provide a method wherein a dried and non-fixed specimen may be rehydrated at the point of use, thus affording the analyst a clear picture of the chromatin.

It is further among the objects of the present invention to provide a composition for carrying out the method, which composition is stable, is easily handled and is highly effective in its application to the slide.

In practicing the present invention there is provided a solution of a water-soluble synthetic film-forming material which preferably also has the property of reducing surface tension. The solvent used is generally a mixture of ethyl ether and ethyl alcohol.

The specimen smear on the slide is treated with the solution by flowing said solution onto the slide to cover the specimen. It is important that the slide be not dipped into the solution as otherwise at least part of the cells of the specimen may be washed off. The solvent is allowed to evaporate, thereby not only fixing the cells but also forming a film thereon to protect it during transit. Before examining the specimen, the slide is then treated with an aqueous ether alcohol liquid which dissolves the film.

Thereafter the slide is stained as usual and is subjected to examination under the microscope.

It has been found that an alkyl cellulose ether soluble in water is an ideal substance for the purpose. Specifically there is provided for immediate fixation and surface coating a capsule containing .2 gram of hydroxy propyl methyl cellulose ether, and dissolving the cellulose ether in 10 cc. of water at a temperature of, say, 80 to 90 C. To this solution is added 190 cc. of a mixture of in 3 parts of water to 2 parts of a mixture of equal equal parts of ethyl alcohol and ethyl ether. The cellulose ether preferably has a viscosity of about 4,000 centipoises although cellulose ethers of other viscosities are also usable.

While in the above description the cellulose ether is in powder form Within a capsule, it is highly feasible to provide a complete solution as stated above in a suitable container such as an ampule, jar, bottle or the like for convenience of the analyst. In such case the analysts preparation of the slide is minimized.

In taking the specimen for examination, a cervical or a vaginal material is placed upon the slide. The specimen may be allowed to dry in the air. In the laboratory the slide is treated with the use of a solution of a surface active agent in water in a suitable concentration. It has been found that the sorbitol or mannitol partial esters of higher fatty acids such as those having 16 and 18 carbon atoms are suitable for the purpose. The specimen is then fixed, stained and examined microscopically.

For rehydration of dried unfixed specimens the capsule containing .2 g. hydroxy propyl methyl cellulose ether has the property of reducing the surface tension of water to about 43 dynes per centimeter, in a solution of 400 cc. of water and 200 cc. of a mixture of 95% ethyl alcohol and ethyl ether. Dried and unfixed slides are dipped in this solution for about five minutes, fixed in ether-alcohol for about ten minutes and then stained.

In the case of endometrial material, or that of gastric origin, breast, urine and others, a somewhat different procedure may be used. The specimen on the slide as soon as the smear is made, is fixed by a mixture of ethyl ether and ethyl alcohol while still fresh usually by dropping said solution upon the specimen on the slide. It is allowed to dry whereby fixation of the cells is obtained and a film formed thereon to protect it. This immediate fixing is important for such specimens since destruction of cells occurs on standing even for a relatively short time. The fixed specimen may be taken to the laboratory for examination. There the slide is placed amounts of ether and alcohol to remove the protective film, stained as usual and examined microscopically.

Although the invention has been described setting forth a single cellulose ether composition, it is apparent that other substances having the desired properties may be used in place thereof. When the specimen has been treated with the solution of .2 g. of cellulose ether in 10 cc. of water and cc. of a mixture of ether and alcohol, it requires, say, twenty to thirty minutes for evaporation of the solvent and it leaves a thin hard film over the specimen. The cells have been fixed and the film protects the material during handling and transit. Therefore, the specimen is in the optimum condition for the microscopic examination. Gastric specimens and those obtained from duodenal drainage undergo rapid enzymatic digestion. If placed in ether-alcohol for fixation while wet, detachment of cells may occur, which is eliminated by this method.

There are a number of advantages inherent in the present invention in that the flowing of the cellulose ether solution onto the slide prevents the washing away of cells and after drying the specimen may be handled even carelessly without damage to the specimen. Because the film is water-soluble, it may easily be washed off and the re-hydration of the specimen is a very simplev operation. The cellulose ether composition is stable and is easy to use. Certain of the specimens smeared onto the slide may be allowed to dry in the air, others may be dehydrated, but the re-hydration makes certain that the specimens are in good condition for examination,

There may be used in the solution of the cellulose i ether different proportions of solvents and in many cases only a single solvent may be used and the concentration of the cellulose ether may be varied. In place of the cellulose ether, other materials having similar'properties may be used or one may apply two substances, one of which is film-forming and the other of which has surface active properties. In re-hydrating the cells, in some instances only water need be used but in order to facilitate the operation and facilitate the examination, the surface acting agent should be present as in such case the re-hydration requires not over about a minute.

While the invention has been described setting forthseveral specific embodiments thereof, the invention is not limited thereto as various changes. in the details may be made within the spirit of the invention and such variations are within the skill of the ordinary worker in the field. Therefore, the invention is to be broadly construed and not to be limited except by the character of claims appended hereto.

I claim:

1. A method of treating slides having thereon smears of body cells for microscopic examination which comprises providing a solution of a Water soluble synthetic film forming material in an ether-alcohol solvent, dropping said solution on said slide to fix said cells, allowing said solvent to evaporate, thereafter treating said slide with an aqueous liquid to dissolve said material, and staining said slide preparatory to microscopic examination.

2. A method according to claim 1 in which said synthetic material is hydroxy propyl methyl cellulose ether.

3. A method of treating slides having thereon smears of body cells for microscopic examination which comprises providing a solution of a water soluble synthetic film forming material in an ether-alcohol solvent, allowing said smears on said slide to dry and then dropping said solution on said slide, allowing said solvent to evaporate, thereafter treating said slide with an aqueous liquid to dissolve said material, and staining said slide preparatory to microscopic examination.

4. A method according to claim 3 in which said'synthetic material is hydroxy propyl methyl cellulose ether.

5. A method of treating slides having thereon smears of body cells for microscopic examination which comprises providing a solution of a water soluble synthetic film forming material in an ether-alcohol solvent, dropping said solution on said slide, said material being an alkyl cellulose ether, allowing said solvent to evaporate, thereafter treating said slide with an aqueous liquid to dissolve said material and to rehydrate said cells, and staining said slide preparatory to microscopic examination.

6. A method of treating slides having thereon smearsi hydroxy propyl methyl cellulose ether, allowing said solvent to evaporate, thereafter treating said slide with an aqueous liquid to dissolve said material, and staining said slide preparatory to microscopic examination.

7. A method of treating slides having thereon smears of body cells for microscopic examination which comprises providing a solution of a water soluble synthetic film forming material in an ether-alcohol solvent, said material being an alkyl cellulose ether, dropping said solution on said slide to dehydrate said cells, allowing said solvent to evaporate, thereafter treating said slide with an aqueous liquid to dissolve said material and to re-hydrate said cells, and staining said slide preparatory to microscopic examination.

8. A method of treating slides having thereon smears of body cells for microscopic examination which comprises providing a solution of a water soluble synthetic film forming material in an ether-alcohol solvent, said material being hydroxy propyl methyl cellulose ether, dropping said solution on said slide to dehydrate said cells, allowing said solvent to evaporate, thereafter treating said slide with an aqueous liquid to dissolve said material and to re-hydrate said cells, and staining said slide preparatory to microscopic examination.

References Cited in the file of this patent UNITED STATES PATENTS 2,265,913 I Lillienfeld Dec. 9, 1941 2,602,755 Silvernail July 8, 1952 2,648,165 Nestor Aug. 11, 1953 

1. A METHOD OF TREATING SIDES HAVING THEREON SMEARS OF BODY CELLS FOR MICROSCOPIC EXAMINATION WHICH COMPRISES PROVIDING A SOLUTION OF A WATER SOLUBLE SYNTHETIC FILM FORMING MATERIAL IN AN ETHER-ALCOHOL SOLVENT, DROPPING SAID SOLUTION ON SAID SLIDE TO FIX SAID CELLS, ALLOWING SAID SOLVENT TO EVAPORATE, THEREAFTER TREATING SAID SLIDE WITH AN AQUEOUS LIQUID TO DISSOLVE SAID MATERIAL, AND STAINING SAID SLIDE PREPARATORY TO MICROSCOPIC EXAMINATION. 